SynopsisThe temperature dependence of the reaction between some metal oxides and an aqueous solution of polyacrylic acid was investigated using the infrared measurements. The obtained data indicated that the divalent metal oxides MgO, ZnO, and PbO react rapidly with the polyacrylic acid forming carboxylate salts. The bonding between the acid groups and these metals is purely ionic in character. The reactivity between these metals and the carboxylic acid is inversely proportional to the radius of metal ions. The reaction of BizO3, Crz03, and TLz03 is far from complete. However, SiOz reacts slowly with polyacrylic acid at 0°C only. The results provided strong evidences that the rate of reaction between some metal oxides and polyacrylic acid depends on the temperature of reaction, This rate of reaction is enhanced as the temperature is lowered.

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SynopsisThe behavior of the electrical conductivity of polycarboxylate cement with temperature was studied from room temperature up to 160OC. The effects of powder/liquid ratio, mixing temperature, percentage of MgO in the powder, and aging on this behavior were also investigated. The results obtained revealed that the electrical conductivity decreases with increasing the powder/liquid ratio and with decreasing mixing temperature and the amount of MgO in the powder. The reason for the changes of the conductivity due to the mentioned factors were discussed.

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